The present application is directed to electronic ballasts. It finds particular application in conjunction with the fluorescent lamps and will be described with the particular reference thereto.
A ballast is an electrical device which is used to provide power to a load, such as an electrical lamp, and to regulate the current provided to the load. The ballast provides high voltage to start a lamp by ionizing sufficient plasma (vapor) for the arc to be sustained and to grow. Once the arc is established, the ballast allows the lamp to continue to operate by providing proper controlled current flow to the lamp.
Typically, after the alternating current (AC) voltage from the power source is rectified and appropriately conditioned, the inverter converts the DC voltage to AC. The inverter typically includes a pair of serially connected switches, such as MOSFETs which are controlled by the drive gate control circuitry to be “ON” or “OFF.”
In conventional voltage fed designs, the inverter does not boost the power applied to the lamps during the glow-arc transition, causing this transition to be slower than desired. Additionally, different sizes and/or lengths of lamps translate into different current requirements, which in turn require conventional inverters to limit the amount of power provided to the lamp terminals.
The following contemplates new methods and apparatuses that overcome the above referenced problems and others.